Sometimes you need to take a hard disk out and take a look at what's inside. This is not always easy to do if you have to install the drive into another unit. The cables may not reach and you may have to play with the jumpers to convert the disk from master to slave mode.
Better yet, you can connect two drives at the same time. This allows you to clone one disk to the other one. If you do a lot of computer installations or repairs, this device could save you many hours of work.
Scythe "Kama Connect" USB2.0 IDA & SATE External Adapter